When I overlap tracks, they aren't in sync :( help!

Special Interest Groups Recording Techniques
1

I’ll record my guitar, and then try to overlap my voice over the guitar part, but it’s never in sync with each other. How can I fix this?

2

You’ll want the Time Shift tool for now:
http://www.guidesandtutorials.com/audacity-toolbars.html

Also, you should be aware that all computers have some latency when recording audio (this is unavoidable).

Newer versions of Audacity have a manually configured latency correction that is easy to set up and quite accurate:
http://audacityteam.org/forum/viewtopic.php?p=5535#p5535